Digital human modelling bags gravity due to the evolution in the healthcare systems along with artificial intelligence. Sedentary lifestyle has made people prone to arthritis of different kinds. Total knee replacement has accustomed orthopaedic care units to rely on the latest technology. These surgeries miss the major arena of ergonomics involved in knee implants across different countries. The study revolves around the implanted knee sizes available to the patients. Comparative analysis of the patients’ basic and segmented knees was done for the Indian population. Mismatch errors were studied along the cutting planes for the femoral condyles at pre- and post-stage. The results from 3D Slicer and Slicer3r pointed towards a gap of 1.87 mm along the Z-axis. Higher mismatch errors along the X and Y axis proposed the requirement of the new implant sizes. Hence, the research contributes to the adverse effects of surgery on the natural knee anatomy.